public void OnBeforeSerialize()
{
var cube = new CubemapHelper {
cubemap = cubemap
};
m_SerializedCubemap = EditorJsonUtility.ToJson(cube, true);
}
//https://stackoverflow.com/questions/34250742/converting-a-cubemap-into-equirectangular-panorama
//https://github.com/adamb70/Python-Spherical-Projection/blob/master/cube2equi.py
//https://stackoverflow.com/questions/11504584/cubic-to-equirectangular-projection-algorithm
private Bitmap ConvertToEquirectangular(CubemapImages cubeMap)
{
CubemapHelper.FillAnyNullWithBlanks(cubeMap);
CubemapHelper.UpsizeAnyPartials(cubeMap);
DirectBitmap[] faces = ResizeAndConverCubeToDirectBitmap(cubeMap);
int cubeFaceWidth = faces[0].Width;
int cubeFaceHeight = cubeFaceWidth;
// this block is to calculate a size that has a comparable pixel density to that of the combined input images
int factor = 256;
int nearestMultiple = 0;
{
int cubePixelCount = cubeFaceHeight * cubeFaceWidth;
int totalCubePixelCount = cubePixelCount * 6;
int sizeToGetComparablePixelDensity = (int)Math.Sqrt(totalCubePixelCount / 2);
nearestMultiple =
(int)Math.Round(
(sizeToGetComparablePixelDensity / (double)factor),
MidpointRounding.AwayFromZero
) * factor;
}
int outputHeight = nearestMultiple + factor; // round it up
int outputWidth = outputHeight * 2;
// make the projection a multiple of the width of the combined images
int scale_factor = 4;
int projectionWidth = (cubeFaceWidth * 4) * scale_factor;
int projectionHeight = projectionWidth / 2;
DirectBitmap equiTexture = new DirectBitmap(projectionWidth, projectionHeight);
//Normalised UV texture coordinates, from 0 to 1, starting at lower left corner
double u_coordinate;
double v_coordinate;
//Polar coordinates
double latitude;
double longitude;
//Unit vector
double x, y, z;
double xAxis, yAxis, zAxis;
double largestComponent;
double[] vector = new double[3];
Color color;
Point pixelCoord;
double normX;
double normY;
//int modulousFactorX = outputWidth / 16;
//int modulousFactorY = outputHeight / 8;
//bool horizontalMarker = false;
//bool verticalMarker = false;
for (int heightIndex = 0; heightIndex < equiTexture.Height; heightIndex++)
{
//verticalMarker = heightIndex % modulousFactorX == 0;
v_coordinate = 1 - ((double)heightIndex / equiTexture.Height);
latitude = v_coordinate * Math.PI;
for (int widthIndex = 0; widthIndex < equiTexture.Width; widthIndex++)
{
//horizontalMarker = widthIndex % modulousFactorY == 0;
u_coordinate = ((double)widthIndex / equiTexture.Width);
longitude = u_coordinate * 2 * Math.PI;
//assuming Y+ is up, X+ is right, Z+ is front
//Calculate unit vector
x = Math.Sin(longitude) * Math.Sin(latitude) * -1;
y = Math.Cos(latitude);
z = Math.Cos(longitude) * Math.Sin(latitude) * -1;
vector[0] = Math.Abs(x);
vector[1] = Math.Abs(y);
vector[2] = Math.Abs(z);
largestComponent = vector.Max();
// PROBLEM : there are cases where the vertical boundary between cube faces
// results in both the x and z components to be equivalent
// so both axis return a 1, which
//Vector Parallel to the unit vector that lies on one of the cube faces
xAxis = x / largestComponent;
yAxis = y / largestComponent;
zAxis = z / largestComponent;
//bool debug = true;
//if (debug && verticalMarker && horizontalMarker)
//{
// MessageBox.Show(
// "h:" + heightIndex + " w:" + widthIndex +
// "\r\nlat:" + latitude + " long:" + longitude +
// "\r\nx:" + x + " y:" + y + " z:" + z
// );
// color = Color.Purple;
//}
if (xAxis == 1)
{
//Right
normX = (((zAxis + 1f) / 2f) - 1f);
normY = (((yAxis + 1f) / 2f));
pixelCoord = GetPixelCoordinates(normX, normY, faces[4].Width, faces[4].Height);
color = faces[4].GetPixel(pixelCoord.X, pixelCoord.Y);
}
else if (xAxis == -1)
{
//Left
normX = ((zAxis + 1) / 2);
normY = ((yAxis + 1) / 2);
pixelCoord = GetPixelCoordinates(normX, normY, faces[3].Width, faces[3].Height);
color = faces[3].GetPixel(pixelCoord.X, pixelCoord.Y);
}
else if (yAxis == -1)
{
//Up
normX = ((xAxis + 1f) / 2f);
normY = ((zAxis + 1f) / 2f);
pixelCoord = GetPixelCoordinates(normX, normY, faces[5].Width, faces[5].Height);
color = faces[5].GetPixel(pixelCoord.X, pixelCoord.Y);
}
else if (yAxis == 1)
{
//Down
normX = ((xAxis + 1f) / 2f);
normY = (((zAxis + 1f) / 2f) - 1f);
pixelCoord = GetPixelCoordinates(normX, normY, faces[1].Width, faces[1].Height);
color = faces[1].GetPixel(pixelCoord.X, pixelCoord.Y);
}
else if (zAxis == 1)
{
//Front
normX = ((xAxis + 1f) / 2f);
normY = ((yAxis + 1f) / 2f);
pixelCoord = GetPixelCoordinates(normX, normY, faces[2].Width, faces[2].Height);
color = faces[2].GetPixel(pixelCoord.X, pixelCoord.Y);
}
else if (zAxis == -1)
{
//Back
normX = (((xAxis + 1f) / 2f) - 1f);
normY = ((yAxis + 1f) / 2f);
pixelCoord = GetPixelCoordinates(normX, normY, faces[0].Width, faces[0].Height);
color = faces[0].GetPixel(pixelCoord.X, pixelCoord.Y);
}
else
{
throw new Exception("Unknown face, something went wrong");
}
equiTexture.SetPixel(widthIndex, heightIndex, color);
}
}
var downscaled = ResizeImage(equiTexture.Bitmap, equiTexture.Width / scale_factor, equiTexture.Height / scale_factor);
return(downscaled);
}